Previous research suggested that earlier intervention may contribute to better outcomes in autism. Answering the question how early? has significant health and educational implications for age of screening and age of entry into early intervention for children with autism spectrum disorders (ASD). With the increased number of young children identified with ASD, there is a pressing need for evidence-based, manualized cost-efficient treatments that are accessible to and feasibly implemented by parents within their natural environments in community-based settings. Significant disparities in diagnosis and treatment of ASD have been found in racial and ethnic minority populations increasing the need for families from diverse cultural and socioeconomic backgrounds. The major objective of Project 3 is to directly compare two parent intervention conditions of the Early Social Interaction Project for 9 months on developmental trajectories of infants showing early risk for ASD. The control treatment is an information, education and support group (IES) offered weekly; the experimental treatment is a parent-implemented intervention (Pll) offered in 2 weekly individualized sessions to teach parents how to embed strategies to support social communication skills within everyday routines, activities, and places, in combination with IES. Project 3 will recruit 92 parent-infant dyads at 12 months of age from the high risk siblings being studied in the Emory ACE Center. High risk infants will screen positive on 2 of 3 screening measures indicating the presence of diagnostic features of ASD by 12 months of age. Families will be randomly assigned to either IES or lES+PII for 9 months. The specific aims of this investigation are: Aim 1) Effectiveness of Treatment- to compare the effectiveness of IES plus Pll on developmental trajectories of social communication, autism symptoms, social visual engagement, developmental skills, and adaptive behavior, compared to IES alone; Aim 2) Mediators of Treatment- to determine whether growth trajectories of child active engagement and parent transactional support are mediators of response to intervention; and Aim 3) Moderators of Treatment: - to identify individual child and family characteristics which predict response to intervention.